This application claims the benefit of Korean Patent Application No. 2001-76986 filed on Dec. 6, 2001, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a duplex printer, and more particularly, to a duplex printer having a multi-function actuator selecting a movement passage of a printing medium according to one side or both sides of the printing medium and removing a jammed printing medium disposed in the movement passage.
2. Description of the Related Art
Generally, a duplex printer can print an image on one side or both sides of a printing medium according to a user selection.
FIG. 1 shows a cross-sectional view of the duplex printer having a conventional actuator. The duplex printer includes a simplex printing passage 10 and a duplex printing passage 20.
The simplex printing passage 10 includes a development unit 11 developing a given image on a printing medium 1 fed by a feeding roller 3, a fixing unit 14 including a pressure roller 12 and a heat roller 13 fixing the developed image on the printing medium 1, a simplex transporting roller 16 transporting a printed printing medium 1 from the fixing unit 14, and a discharge roller 5 discharging the printed printing medium 1 to a discharge tray 7.
A duplex printing passage 20 includes a plurality of duplex transporting rollers 21,22,23 transporting the printing medium 1, which has been printed on the one side thereof and is transported from the discharge roller 5 to the feeding roller 3.
Also, an actuator 30 has one end 31 being hinged at a duplex printer frame and is disposed among the discharge roller 5, the simplex transporting roller 16, and the duplex transporting roller 21. Therefore, the simplex printing passage 10 or the duplex printing passage 20 can be selected by moving the actuator 30.
In the duplex printer, an operation of printing one side or both sides of the printing medium 1 is described as follows.
When printing on one side of the printing medium 1, the printing medium 1 passes through the fixing unit 14 and is transported to the discharge roller 5 by the simplex transporting roller 16 and then discharged in a discharging direction to the discharge tray 7 by the discharge roller 5. At this time, the printing medium 1, which passes through the simplex transporting roller 16, is freely moved into the discharge roller 5 because the actuator 30 is positioned at a first position P1.
Also, when printing on both sides of the printing medium 1, first, the printing medium 1, which has been printed on the one side thereof through the operation described above, is moved into the discharge roller 5. And then the discharge roller 5 is rotated in a reverse direction before the printing medium 1 moves away from the discharge roller 5 so that the printing medium 1 is moved in an opposite direction. At this time, because the actuator 30 is located at a second position P2, the printing medium 1, moved in the direction opposite to the discharging direction, can be moved into the duplex printing passage 20. And then the printing medium 1 printed on the one side thereof is transported to the development unit 11 by the duplex transporting rollers 21, 22, 23 and the feeding roller 3. Here, the other side of the printing medium 1 is turned to face upward by the duplex transporting rollers 21, 22, 23 and the feeding roller 3. Then the printing medium 1 printed on the one side thereof is printed on the other side by the development unit 11 and the fixing unit 14 and discharged to the discharge tray 7 by the discharge roller 5. Accordingly, the printing medium 1 can be printed on both sides thereof by the actuator 30.
FIG. 2 shows a cross-sectional view of another type of duplex printer having another conventional actuator. The actuator 40 is rotatable disposed above the pressure roller 62 and includes a body 41, a duplex guide 43, a sensor arm 45, and an actuator separator 47 independently projecting in a predetermined direction from the body 41. Also, the duplex guide 43, the sensor arm 45, and the actuator separator 47 are integrally formed with the body 41.
The body 41 has a cylindrical shape, and both ends thereof are rotatable disposed at an upper part of a frame where a pressure roller 62 is disposed.
The duplex guide 43 projects from the body 41, is disposed above a heat roller 63, and rotates upward by an interference with a front end of the printing medium 1 passing through the fixing unit 64.
The sensor arm 45 projects from a vicinity of one end of the body 41 in an upward direction relative to the duplex guide 43 at an angle of approximately 120xc2x0 with respect to the duplex guide 43. When the duplex guide 43 is in a horizontal position, an upper part of the sensor arm 45 is detected by using a sensor 49 mounted on the duplex printer frame.
The actuator separator 47 projects from a vicinity of an opposite end of the body 41 in the upward direction relative to the duplex guide 43 at an angle of approximately 90xc2x0. The actuator separator 47 is used for manually rotating the duplex guide 43 by a predetermined angle to remove a jammed printing medium 1. Accordingly, the jammed printing medium 1 to be removed from the fixing unit 64 is not blocked by the duplex guide 43 during removal of the jammed printing medium 1.
In the duplex printer having the actuator 40 constructed as above, a duplex printing operation is performed as follows.
The printing medium 1 passes through the fixing unit 64 with the one side printed, the duplex guide 43 rotates by the front end of the printing medium 1 by a predetermined angle, and the printing medium 1 is moved into the discharge passage 50.
After a trailing end of the printing medium 1 moves into the discharge passage 50 and does not contact the duplex guide 43, the discharge roller 53 is rotated in the reverse direction so that the printing medium 1 is moved in the opposite direction. At this time, because the duplex guide 43, which rotates downward to the horizontal position by a weight thereof, blocks above the fixing unit 64 and the printing passage 60, the printing medium 1 moves in the opposite direction into the duplex printing passage 70.
The printing medium 1 moved into the duplex printing passage 70 moves into the development unit 61 by a transfer roller 71 again, and then is printed on a non-printed side. Then the printing medium 1 printed on both sides thereof is discharged to the discharge tray 80 by the discharge rollers 51,53. Accordingly, the printing medium 1 can be printed on both sides thereof by the operation of the actuator 40.
However, in the duplex printer constructed as shown in FIG. 1, there is a problem that the jammed printing medium 1 cannot be removed by the actuator 30 when the jammed printing medium 1 is jammed in the fixing unit 14. Therefore, a separate additional apparatus removing the jammed printing medium 1 is needed.
Also, in the duplex printer constructed as shown in FIG. 2, there is another problem that the jammed printing medium 1 is blocked by the duplex guide 43 when the jammed printing medium 1 is removed from the fixing unit 64 or the discharge passage 50.
There is another problem that the separate additional apparatus separating the pressure roller 62 and the heat roller 63 of the fixing unit 64 requires a free space in which the separate additional apparatus is disposed.
Therefore, it is an object of the present invention to provide a multi-function actuator having an actuator separating a pressure roller from a heat roller by an actuator separator so that a jammed printing medium is easily removed from a fixing unit.
Another object of the present invention is to provide a multi-function actuator, in which a duplex guide is disposed apart from a movement passage of a printing medium so that a jammed printing medium is easily removed from a discharge passage.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and other objects, a multi-function actuator according to an embodiment of the present invention includes a duplex guide rotatable disposed above a pressure roller of a duplex printer frame. The duplex guide includes a hollow cylinder and a plurality of bar-shaped guide pins formed at one side of the hollow cylinder and arranged in a row above a heat roller to guide a printing medium. The duplex guide is rotated by the printing medium by a guide angle in a printing medium feeding direction from a first position blocking a printing passage of the printing medium to a second position opening the printing passage. The multi-function actuator includes a jam removing mechanism rotatable disposed inside of the hollow cylinder to allow the pressure roller to be separated from the heat roller when a jammed printing medium is removed, a sensor arm disposed co-axially with the duplex guide to rotate by a weight of the sensor arm and having a low part supported by a supporting end of the duplex guide to form a first predetermined angle between the sensor arm and the guide pins, and a sensor disposed at the duplex printer frame to sense the sensor arm when the duplex guide is rotated by the printing medium.
Further, the jam removing mechanism includes a jam removing lever rotatable disposed at the duplex printer frame and on a side of the pressure roller and having a penetrating hole disposed at a middle part thereof, into which a rotation shaft of the pressure roller is inserted, a jam removing shaft inserted inside of the hollow cylinder and rotatable disposed at the duplex printer frame, an actuator separator attached on one side of the jam removing shaft to rotate the jam removing shaft by a second predetermined angle in the printing medium feeding direction to allow the printing medium jammed between the pressure roller and the heat roller to be removed, and a jam removing cam disposed on another side of the jam removing shaft to contact an upper portion of the jam removing lever and formed such that if the actuator separator rotates at the second predetermined angle, the jam removing lever is rotated by the jam removing cam by a third predetermined angle in the same printing medium feeding direction to separate the pressure roller from the heat roller.
Further, the actuator separator includes a rib rotating the duplex guide when the jammed printing medium is removed.
Further, the duplex guide is rotated at an angle of 60 degrees in the printing medium feeding direction by the printing medium when the printing medium is printed, and further rotates at an angle of 180 degrees by a weight of the duplex guide after the duplex guide rotates at an angle of 110 degrees by the rib of the actuator separator when the jammed printing medium is removed.
Further, the actuator separator is spaced apart from the jam removing cam at a predetermined distance where the printing medium passes.
Further, the actuator separator and the jam removing cam project in the substantially same direction.
Further, the jam removing mechanism includes a second jam removing cam disposed on a third side of the jam removing shaft opposite to the another side to be spaced-apart from the jam removing cam by a second predetermined distance so that the printing medium passes between the two jam removing cams.